So every one is stumped about this? There are other problems with this project but right now I just want to know since this whole block may be considered one building because of no fire walls but has many lot lines with different owners and different occupancies do I add the sq ft of the second floor and basements of the whole block to to get the aggregate area which would be over 3,000 sq ft and require the basement and 2nd floor to have an accessible route?
For the application of accessibility requirements, I would consider each structure within the lot lines to be an "independent building," especially if there are no openings between the independent buildings.
If each independent building has its own entrance and circulation system (corridors, stairs, elevators, etc.), I cannot see how the DOJ would interpret the connected string of individually-owned units on separate lots to be one large building that is subject to the whims of any one of its owners. The ADA does not address changes of occupancy, it is only concerned with the physical modifications of a building. Thus, all requirements for historic buildings address alterations. If your project includes alterations as part of the change of occupancy, Section 206.2.3, Exception 7, of the 2010 ADA Standards states the building would "not be required to provide an accessible route to stories located above or below the accessible story." Keep in mind, though, this only applies to "qualified" historic buildings, so make sure it conforms to the definition in Chapter 1 of the 2010 ADA Standards.
I would like to think that those interpreting the ICC
accessibility requirements would have the same interpretation; however, considering the IBC covers fire and life safety, those requirements could dictate a different opinion if you started with the IBC. However, for existing historic buildings, much of the IBC does not apply since the IEBC should be your starting point, and would need to only comply with the IBC when required by the IEBC.
IEBC Section 306.7.16.2 states that multiple-level historic buildings and facilities undergoing alterations or changes of occupancy need only provide "an accessible route from an accessible entrance to public spaces on the level of the accessible entrance." Thus, basements and upper floors would not be required to have an accessible route.